The GKGameCenterControllerDelegate protocol is implemented by delegates of the
GKGameCenterViewController class. The delegate is called when the player dismisses the Game Center user interface.
Called when the player is done interacting with the view controller’s content.
- (void)gameCenterViewControllerDidFinish:(GKGameCenterViewController *)
The view controller the player finished interacting with.
Your delegate should dismiss the Game Center view controller. If your game paused any gameplay or other activities, it can restart those services in this method.
Available in iOS 6.0 and later.